/*******************************************************************************
 * Copyright (c) 2014 Ericsson and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *   Marc Khouzam (Ericsson) - Support Dynamic Printf (Bug 400628)
 *******************************************************************************/

package org.eclipse.cdt.dsf.gdb.breakpoints;

import org.eclipse.cdt.dsf.concurrent.Immutable;
import org.eclipse.osgi.util.NLS;


/**
 * Utility methods to help deal with Dynamic Printf logic.
 * 
 * @since 4.4
 */
public class GDBDynamicPrintfUtils {

	@Immutable
	public static class GDBDynamicPrintfString {
		private boolean fValid;
		private String fStringSection;
		private String[] fArgs;
		private String fErrorMessage;
		
		public GDBDynamicPrintfString(String str) {
			if (str == null) {
				fErrorMessage = Messages.DynamicPrintf_Invalid_string;
				return;
			}
			
			str = str.trim();
			
			// No point in having an empty string, just disable the dprintf instead
			if (str.isEmpty()) {
				fErrorMessage = Messages.DynamicPrintf_Invalid_string;
				return;
			}
			
			// First character must be a double-quote
			if (str.charAt(0) != '"') {
				fErrorMessage = Messages.DynamicPrintf_Printf_must_start_with_quote;
				return;
			}

			// Now go through the string and look for two things:
			//   1- count the number of % (but ignore any %%)
			//   2- find the closing double-quote (but ignore any \")
			char[] chars = str.toCharArray();
			int closingQuoteIndex = 0;
			int numArgExpected = 0;
			for (int i=1; i<chars.length; i++) {
				switch (chars[i]) {
				case '\\':
					// Next char can be ignored
					i++;
					break;
				case '"':
					closingQuoteIndex = i;
					break;
				case '%':
					if (chars.length > i+1 && chars[i+1] != '%') {
						// Not a %% so we have found an expected argument.
						numArgExpected++;
					}

					// We either found a second %, which we must skip to
					// avoid parsing it again, or we didn't and we know
					// our next character must be part of the format.
					// In both cases we can and should skip the next character.
					// Note that we are not going to make sure the format is
					// correct as that becomes really complex.
					i++;
					break;
				}
				
				// If we found the closing double-quote, there is no need to keep counting
				if (closingQuoteIndex > 0) break;
			}
			
			if (closingQuoteIndex < 1) {
				// Didn't find a closing double-quote!
				fErrorMessage = Messages.DynamicPrintf_Printf_missing_closing_quote;
				return;
			}

			// We extract the string part of the printf string leaving the arguments
			fStringSection = str.substring(0, closingQuoteIndex+1);
			
			int numArgPresent = 0;
			if (closingQuoteIndex + 1 >= str.length()) {
				// No more characters after the string part
				fArgs = new String[0];
				numArgPresent = 0;
			} else {
				String argString = str.substring(closingQuoteIndex+1).trim();
				if (argString.charAt(0) != ',') {
					fErrorMessage = Messages.DynamicPrintf_Missing_comma;
					return;
				}
				
				// Remove the first , to avoid an empty element after the split.
				// Then split the string but keep any empty results
				String[] args = argString.substring(1).split(",", -1); //$NON-NLS-1$

				for (String argument : args) {
					if (argument.trim().isEmpty()) {
						fErrorMessage = Messages.DynamicPrintf_Empty_arg;
						return;
					}
				}

				fArgs = args;
				numArgPresent = fArgs.length;
			}

			if (numArgPresent != numArgExpected) {
				if (numArgPresent > numArgExpected) {
					fErrorMessage = NLS.bind(Messages.DynamicPrintf_Extra_arg, numArgPresent - numArgExpected);
				} else {
					fErrorMessage = NLS.bind(Messages.DynamicPrintf_Missing_arg, numArgExpected - numArgPresent);
				}
				return;
			}
			
			// Everything is ok!
			fValid = true;
		}
		
		public boolean isValid() {
			return fValid;
		}
		
		public String getString() {
			if (!isValid()) return ""; //$NON-NLS-1$
			return fStringSection;
		}
		
		public String[] getArguments() {
			if (!isValid()) return new String[0];
			return fArgs;
		}
		
		public String getErrorMessage() {
			return fErrorMessage;
		}
	}	
}